First Monte Carlo Global Analysis of Nucleon Transversity with Lattice QCD Constraints

We report on the first global QCD analysis of the quark transversity distributions in the nucleon from semi-inclusive deep-inelastic scattering (SIDIS), using a new Monte Carlo method based on nested sampling and constraints on the isovector tensor charge g(T) from lattice QCD. A simultaneous fit to the available SIDIS Collins asymmetry data is compatible with g(T) values extracted from a comprehensive reanalysis of existing lattice simulations, in contrast to previous analyses, which found significantly smaller g(T) values. The contributions to the nucleon tensor charge from u and d quarks are found to be delta u = 0.3(2) and delta d = -0.7(2) at a scale Q(2) = 2 GeV2.